@inproceedings{hu-etal-2026-ci,
title = "{CI}-{RELAY}: Contextual Integrity Mediation for Privacy in {LLM}-based Multi-Agent Systems",
author = "Hu, Runshan and
Dong, Yukun and
Bi, Jia and
Zhu, Chenyang",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {EMNLP} 2026",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.findings-emnlp.2421/",
doi = "10.18653/2026.findings-emnlp.2421",
pages = "51981--52001",
ISBN = "979-8-89176-462-0",
abstract = "Multi-agent systems powered by large language models (LLMs) increasingly decompose tasks by passing natural-language relays among specialized agents. This creates a boundary-level privacy failure: a non-entitled internal agent can learn private context before any final-output guard or tool-action checker observes a violation. We introduce contextual-integrity mediation for inter-agent communication, a formulation in which each candidate relay is treated as a commit that must satisfy recipient entitlement, attribute minimization, and transmission conditions before delivery. We present CI-Relay, a runtime mediation layer that induces CI scopes from runtime-visible norms and relay metadata, packages candidate messages as CI-labeled envelopes, projects recipient-scoped views, propagates transmission constraints, and records auditable mediation traces. On relay traces converted from three CI benchmarks, unmediated relays leak internally in 52.2{\%} of cases. Relative to a metadata-matched LLM Guard Relay that receives the same induced scope, CI-Relay reduces internal leakage from 12.4{\%} to 1.8{\%} and downstream leakage from 10.9{\%} to 5.6{\%}, while improving utility and reducing over-redaction. Gains hold across three live LLM backends; multi-hop, prompt-robustness, and ablation studies show that the gains arise from structured CI mediation rather than generic privacy prompting, guard rewriting, or final-output checking."
}<?xml version="1.0" encoding="UTF-8"?>
<modsCollection xmlns="http://www.loc.gov/mods/v3">
<mods ID="hu-etal-2026-ci">
<titleInfo>
<title>CI-RELAY: Contextual Integrity Mediation for Privacy in LLM-based Multi-Agent Systems</title>
</titleInfo>
<name type="personal">
<namePart type="given">Runshan</namePart>
<namePart type="family">Hu</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Yukun</namePart>
<namePart type="family">Dong</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Jia</namePart>
<namePart type="family">Bi</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Chenyang</namePart>
<namePart type="family">Zhu</namePart>
<role>
<roleTerm authority="marcrelator" type="text">author</roleTerm>
</role>
</name>
<originInfo>
<dateIssued>2026-10</dateIssued>
</originInfo>
<typeOfResource>text</typeOfResource>
<relatedItem type="host">
<titleInfo>
<title>Findings of the Association for Computational Linguistics: EMNLP 2026</title>
</titleInfo>
<name type="personal">
<namePart type="given">Hung-Yi</namePart>
<namePart type="family">Lee</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Sunipa</namePart>
<namePart type="family">Dev</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Jessy</namePart>
<namePart type="family">Li</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<name type="personal">
<namePart type="given">Desmond</namePart>
<namePart type="family">Elliott</namePart>
<role>
<roleTerm authority="marcrelator" type="text">editor</roleTerm>
</role>
</name>
<originInfo>
<publisher>Association for Computational Linguistics</publisher>
<place>
<placeTerm type="text">Budapest, Hungary</placeTerm>
</place>
</originInfo>
<genre authority="marcgt">conference publication</genre>
<identifier type="isbn">979-8-89176-462-0</identifier>
</relatedItem>
<abstract>Multi-agent systems powered by large language models (LLMs) increasingly decompose tasks by passing natural-language relays among specialized agents. This creates a boundary-level privacy failure: a non-entitled internal agent can learn private context before any final-output guard or tool-action checker observes a violation. We introduce contextual-integrity mediation for inter-agent communication, a formulation in which each candidate relay is treated as a commit that must satisfy recipient entitlement, attribute minimization, and transmission conditions before delivery. We present CI-Relay, a runtime mediation layer that induces CI scopes from runtime-visible norms and relay metadata, packages candidate messages as CI-labeled envelopes, projects recipient-scoped views, propagates transmission constraints, and records auditable mediation traces. On relay traces converted from three CI benchmarks, unmediated relays leak internally in 52.2% of cases. Relative to a metadata-matched LLM Guard Relay that receives the same induced scope, CI-Relay reduces internal leakage from 12.4% to 1.8% and downstream leakage from 10.9% to 5.6%, while improving utility and reducing over-redaction. Gains hold across three live LLM backends; multi-hop, prompt-robustness, and ablation studies show that the gains arise from structured CI mediation rather than generic privacy prompting, guard rewriting, or final-output checking.</abstract>
<identifier type="citekey">hu-etal-2026-ci</identifier>
<identifier type="doi">10.18653/2026.findings-emnlp.2421</identifier>
<location>
<url>https://aclanthology.org/2026.findings-emnlp.2421/</url>
</location>
<part>
<date>2026-10</date>
<extent unit="page">
<start>51981</start>
<end>52001</end>
</extent>
</part>
</mods>
</modsCollection>
%0 Conference Proceedings
%T CI-RELAY: Contextual Integrity Mediation for Privacy in LLM-based Multi-Agent Systems
%A Hu, Runshan
%A Dong, Yukun
%A Bi, Jia
%A Zhu, Chenyang
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Findings of the Association for Computational Linguistics: EMNLP 2026
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-462-0
%F hu-etal-2026-ci
%X Multi-agent systems powered by large language models (LLMs) increasingly decompose tasks by passing natural-language relays among specialized agents. This creates a boundary-level privacy failure: a non-entitled internal agent can learn private context before any final-output guard or tool-action checker observes a violation. We introduce contextual-integrity mediation for inter-agent communication, a formulation in which each candidate relay is treated as a commit that must satisfy recipient entitlement, attribute minimization, and transmission conditions before delivery. We present CI-Relay, a runtime mediation layer that induces CI scopes from runtime-visible norms and relay metadata, packages candidate messages as CI-labeled envelopes, projects recipient-scoped views, propagates transmission constraints, and records auditable mediation traces. On relay traces converted from three CI benchmarks, unmediated relays leak internally in 52.2% of cases. Relative to a metadata-matched LLM Guard Relay that receives the same induced scope, CI-Relay reduces internal leakage from 12.4% to 1.8% and downstream leakage from 10.9% to 5.6%, while improving utility and reducing over-redaction. Gains hold across three live LLM backends; multi-hop, prompt-robustness, and ablation studies show that the gains arise from structured CI mediation rather than generic privacy prompting, guard rewriting, or final-output checking.
%R 10.18653/2026.findings-emnlp.2421
%U https://aclanthology.org/2026.findings-emnlp.2421/
%U https://doi.org/10.18653/2026.findings-emnlp.2421
%P 51981-52001
Markdown (Informal)
[CI-RELAY: Contextual Integrity Mediation for Privacy in LLM-based Multi-Agent Systems](https://aclanthology.org/2026.findings-emnlp.2421/) (Hu et al., Findings 2026)
ACL